Nanoparticle-enhanced phase change materials (NePCMs) are nanofluids that can be used for thermal energy storage when they undergo solid-liquid phase transitions. In this study, a Thermal Constants Analyzer (TPS) measured the thermal conductivity of eicosane-based NePCM samples using the transient plane source (TPS) method. Results showed that thermal conductivity of the solid composites increased with temperature, and eicosane-CuO samples that solidified in an ice-water bath had the lowest thermal conductivities, ...